Justice Norvienyeku

Wheat (Triticum aestivum L.) is one of the important food crops worldwide and plays a crucial role in ensuring global food security. It represents a major source of calories and plant-derived prote...

Sweet sorghum (Sorghum bicolor L. Moench) is widely recognized as a strategic bioenergy crop for semi-arid and dryland environments because of its high fermentable sugar content and low water requi...

Apigenin is a natural plant flavonoid known for its remarkable biological activity. While numerous studies have documented the accumulation of glycosylated and non-glycosylated apigenin in fruit and vegetable crops, apigenin's direct and indirect effects on plant resistance remain poorly understood. This study employed non-targeted metabolomics strategies to monitor metabolome-reprogramming events in susceptible, moderately resistant, and highly resistant pepper ( Capsicum annuum) cultivars challenged with Phytophthora capsici . Results revealed a positive correlation between the accumulation of apigenin and apigenin-7-O- β -d-glucoside in pepper seedlings inoculated with P. capsici and the resistance characteristics of the individual pepper cultivars. Further, we demonstrated that both apigenin and apigenin-7-O- β -d-glucoside significantly inhibited the vegetative growth of economically important phytopathogenic oomycetes and fungi, including P. capsici , P. sojae , Pyricularia oryzae , Fusarium graminearum , and Colletotrichum siamense . These findings highlight the potential applications of glycosylated and non-glycosylated apigenin in developing biopesticides to support the environment-friendly prevention and control of critical crop fungal and oomycete diseases. Graphical abstract

Cowpea Fusarium wilt (CFW) is a soilborne fungal disease caused by Fusarium oxysporum f. sp. tracheiphilum (Fot), leading to substantial yield losses globally. This study evaluates the biocontrol potential of Bacillus velezensis HAB-2 and develops a microbial combination for effective disease management. B. velezensis HAB-2 suppressed F. oxysporum f. sp. tracheiphilum AIQBFO93 growth by 69.8% in vitro and exhibited multiple plant growth-promoting traits. Pot experiments demonstrated that HAB-2 alone achieved a 47.62% control rate against CFW. Furthermore, two compatible plant growth-promoting rhizobacteria (PGPR), Pseudomonas hunanensis HD33 and Enterobacter soli HD42, were isolated from the rhizosphere soil of cowpea previously treated with HAB-2. These two strains were combined with HAB-2 at different concentrations in 15 microbial combinations. The combined application of the three strains provided more consistent disease control, with the optimal combination demonstrating a 15.15% higher control rate than HAB-2 alone. Compared to the untreated control, this combination significantly increased cowpea fresh weight, leaf area, and plant height by 10.60%, 8.04%, and 7.81%, respectively, and upregulated the expression of defense-related genes, indicating enhanced resistance. These results confirm that B. velezensis HAB-2 is an effective biocontrol agent against wilt disease, and its synergistic application with functionally complementary PGPR strains provides a viable strategy for sustainable crop disease management.

Over 50% of arable land available for cereal production in sub‐Saharan Africa is severely infested with Striga hermonthica (Del.) Benth, posing a significant challenge to agricultural productivity in the region. In this study, we performed association mapping of plant height, panicle height, number of leaves per plant, field fresh grain weight, dry grain weight, and chlorophyll with 6,094,317 single nucleotide polymorphism (SNP) markers for Striga resistance genes in diverse sorghum [ Sorghum bicolor (L.) Moench] breeding lines and varieties released for resistance breeding. Chromosomes containing significant SNPs in FASTmrMLM and FarmCPU models were identified and computed. Chromosomes 1, 2, 3, 4, and 6 harbored SNPs significant for Striga tolerance in sorghum for agronomic‐related traits. Agronomic traits measured revealed significant SNP counts as follows: plant height (4), panicle height (3), leaves per plant (2), foliar fresh grain weight (8), dry grain weight (2), and chlorophyll content (3). After successful validation, the 22 newly identified SNP markers linked to Striga resistance can be used for trait introgression and marker‐assisted selection to increase Striga resistance in sorghum. We detected 12 SNPs using the FASTmrMLM model without adjusting the threshold level. However, no significant SNPs were detected with FarmCPU before the threshold was adjusted. Also, we identified 95 significant SNPs upon lowering the Bonferroni threshold value to p  < 0.001. The parent materials for the intraspecific cross that produced the currently accessible molecular map were selected from the gene pool of cultivated sorghum. This map is invaluable for real‐world breeding applications. Subsequent crosses among cultivated sorghum genotypes of interest to breeders will likely produce polymorphic segregating Diversity Array Technology (DArTSeq) markers within the cultivated gene pool.

Phytopathogenic oomycetes, particularly Phytophthora capsici, the causal agent of Phytophthora blight disease in essential vegetables and fruit crops, remains a persistent challenge in the vegetable production industry. However, the core molecular regulators of the pathophysiology and broad-range host characteristics of P. capsici remain unknown. Here, we used transcriptomics and CRISPR-Cas9 technology to functionally characterize the contributions of a novel gene (PcTBCC1) coding for a hypothetical protein with a tubulin-binding cofactor C domain with a putative chloroplast-targeting peptide (cTP) to the pathophysiological development of P. capsici. We observed significant upregulation in the expression of PcTBCC1 during pathogen–host interactions. However, the vegetative growth of the ∆Pctbcc1 strains was not significantly different from the wild-type strains. PcTBCC1 gene replacement significantly compromised the sporulation, pathogenic differentiation, and virulence of P. capsici. At the same time, ∆Pctbcc1 strains were sensitive to cell wall stress-inducing osmolytes. These observations, coupled with the close evolutionary ties between PcTBCC1 and pathogenic oomycetes and algae, partly support the notion that PcTBCC1 is a conserved determinant of pathogenesis. This study provides insights into the significance of tubulin-binding cofactors in P. capsici and underscores the potential of PcTbcc1 as a durable target for developing anti-oomycides to control phytopathogenic oomycetes.

Photodependent processes, including circadian rhythm, autophagy, ubiquitination, neddylation/deneddylation, and metabolite biosynthesis, profoundly influence microbial pathogenesis. Although a photomorphogenesis signalosome (COP9/CSN) has been identified, the mechanism by which this large complex contributes to the pathophysiological processes in filamentous fungi remains unclear. Here, we identified eight CSN complex subunits in the rice blast fungus Magnaporthe oryzae and functionally characterized the translocon subunits containing a nuclear export or localization signal (NES/NLS). Targeted gene replacement of these CSN subunits, including MoCSN3, MoCSN5, MoCSN6, MoCSN7, and MoCSN12, attenuated vegetative growth and conidiation and rendered the deletion strains nonpathogenic. MoCSN7 deletion significantly suppressed arachidonic acid catabolism, and compromised cell wall integrity in M. oryzae. Surprisingly, we also discovered that MoCSN subunits, particularly MoCsn7, are required for the cAMP-dependent regulation of autophagic flux. Therefore, MoCSN significantly contributes to morphological, physiological, and pathogenic differentiation in M. oryzae by fostering cross-talk between multiple pathways.

Dynamic transposition of transposable elements (TEs) in fungal pathogens has significant impact on genome stability, gene expression, and virulence to the host. In Magnaporthe oryzae , genome plasticity resulting from TE insertion is a major driving force leading to the rapid evolution and diversification of this fungus. Despite their importance in M. oryzae population evolution and divergence, our understanding of TEs in this context remains limited. Here, we conducted a genome-wide analysis of TE transposition dynamics in the 11 most abundant TE families in M. oryzae populations. Our results show that these TEs have specifically expanded in recently isolated M. oryzae rice populations, with the presence/absence polymorphism of TE insertions highly concordant with population divergence on Geng/ Japonica and Xian/ Indica rice cultivars. Notably, the genes targeted by clade-specific TEs showed clade-specific expression patterns and are involved in the pathogenic process, suggesting a transcriptional regulation of TEs on targeted genes. Our study provides a comprehensive analysis of TEs in M. oryzae populations and demonstrates a crucial role of recent TE bursts in adaptive evolution and diversification of the M. oryzae rice-infecting lineage. IMPORTANCE: Magnaporthe oryzae is the causal agent of the destructive blast disease, which caused massive loss of yield annually worldwide. The fungus diverged into distinct clades during adaptation toward the two rice subspecies, Xian/ Indica and Geng/ Japonica . Although the role of TEs in the adaptive evolution was well established, mechanisms underlying how TEs promote the population divergence of M. oryzae remain largely unknown. In this study, we reported that TEs shape the population divergence of M. oryzae by differentially regulating gene expression between Xian/ Indica -infecting and Geng/ Japonica -infecting populations. Our results revealed a TE insertion-mediated gene expression adaption that led to the divergence of M. oryzae population infecting different rice subspecies.